DIV I 



BRYOPHYTA 



493 



Order l. Sphagnales ( 109 ) 



The Sphagnaceae, or Bog Mosses, are the only family and include only a single 

 genus, Sphagnum, containing many species. The Bog Mosses grow in swampy places, 

 and form large tussocks 

 saturated with water. 

 The upper extremities of 

 the stems continue their 

 growth from year to year, 

 while the lower portions 

 die away and become 

 eventually converted into 

 peat. Of the numerous 

 lateral branches arising 

 from each of the shoots, 

 some grow upwards and 

 form the apical tufts or 

 heads at the summits of 

 the stems ; others, which 

 are more elongated and 

 flagelliform in shape, turn 

 downwards and envelop p IG> 4tt.Schistostega osmundacea. A, Sterile ; B, fertile plant, 

 the lower portions of the (x 5.) C, Protonema. (x 90. After NOLL.) 



stem (Fig. 452^4). Every 

 year one branch below the apex develops as strongly as the mother shoot, so 



FIG. 456. Mu iu HI iindulatum. Orthotropous 

 shoot terminating in a male receptacle sur- 

 rounded by involucral leaves. The lateral 

 shoots are plagiotropous. (After GOEBEL.) 



FIG. 457. Scleropodium purum. (Nat. size.) 



that the stem becomes falsely bifurcated. By the gradual death of the stem 

 from below upwards the daughter shoots become separated from it, and form 



